1. Field of the Invention
The present teachings relate to electrocatalyst compositions composed essentially of platinum, titanium, a third metal, a fourth metal and a fifth metal. The platinum can be present in an atomic percentage ranging between about 30 percent and about 85 percent, titanium can be present in an atomic percentage ranging between about 5 percent and about 30 percent, the third metal can be present in an atomic percentage ranging between about 1 percent and about 30 percent, the fourth metal can be present in an atomic percentage ranging between about 1 percent and about 30 percent, the fifth metal can be present in an atomic percentage ranging between about 1 percent and about 30 percent.
The third metal can be at least one member selected from the group consisting of nickel, vanadium, molybdenum, copper, manganese, iron, cobalt, ruthenium, rhodium, palladium, silver, osmium, iridium and gold. The fourth and fifth metals are different from each other and the third metal and can each be at least one member selected from the group consisting of scandium, vanadium, chromium, manganese, iron, nickel, copper, zinc, yttrium, zirconium, niobium, molybdenum, cadmium, tin, hafnium, tantalum and rhenium.
2. Discussion of the Related Art
The desire to reduce the amount of expensive platinum group metals needed to obtain a desired level of performance for an electrocatalyst is an ever present operational parameter for the design of many devices and procedures involving electrocatalysts.
Enhancement of catalytic performance by combining platinum with various less expensive metals is one of the possible avenues to reduce the amount of platinum required, or increase the efficiency of the catalyzed reaction, or both. One application of interest for Pt-based electrocatalyst is, for instance, the cathode reaction of a typical proton exchange membrane fuel cell (“PEMFC”) which can utilize an electrode containing a Pt-based electrocatalyst to catalyze the oxygen reduction reaction.
A need exists for electrocatalyst compositions and thin film fuel cell electrocatalysts that reduce the amount of platinum needed to achieve a desired performance level.